/*
 * This file is part of Catfish.
 * Copyright (C) 2010 Namazu Studios LLC
 * 
 * Catfish is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation, either version 3 of 
 * the License, or (at your option) any later version.
 * 
 * Catfish is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with Catfish.  If not, please visit:
 *  
 * http://www.gnu.org/licenses/
 *  
 */
package com.namazustudios.catfish.converter;

import java.lang.reflect.Type;

import com.google.appengine.api.datastore.Key;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Singleton;
import com.namazustudios.catfish.CatfishException;
import com.namazustudios.catfish.annotation.Name;
import com.namazustudios.catfish.reference.WeakReference;

/**
 * Converts Keys to weak references.
 * 
 * @author patricktwohig
 * 
 */
@Singleton
@Name(name = "weak")
public class WeakReferenceConverter implements Converter<Key, WeakReference<?>> {

	@Inject
	private Injector injector;

	@Override
	public WeakReference<?> load(Type type, WeakReference<?> existing, Key obj) {

		if (existing == null) {
			throw new CatfishException("WeakReferences must not be null " +
					"prior to unmarshalling.");
		}

		injector.injectMembers(existing);
		existing.setKey(obj);

		return existing;
	}

	@Override
	public Key store(WeakReference<?> obj) {

		if (obj == null) {
			throw new CatfishException("Weakreferences must not be null" +
					"prior to marshalling.");
		}

		injector.injectMembers(obj);
		return obj.getKey();
	}

}
